Internal photoluminescence in ZnSe homoepitaxy and application in blue-green-orange mixed-color light-emitting diodes

H. Wenisch*, M. Fehrer, M. Klude, Kazuhiro Ohkawa, D. Hommel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

We discuss the controllable color-range in ZnSe-based light-emitting diodes (LEDs) realized by ZnSe homoepitaxy and internal photoluminescence. ZnSe-based LED structures were grown by molecular-beam epitaxy (MBE) on mostly conductive ZnSe substrates, which exhibit under short wavelength light excitation at room temperature strong orange emission around 600 nm. This fact is exploited to fabricate integrated mixed-color LED chips, where light from the active layer sandwiched in a p-n-junction acts as internal excitation source. We named this effect recently 'Internal Photoluminescence' (Wenisch et al., J. Appl. Phys. 82 (1997) 4690). It leads to electroluminescence spectra with two distinct emission peaks originated from the active layer and from the ZnSe substrate, respectively. In view of color impression, just by varying the CdxZn1-xSe quantum-well composition and the radiant recombination rate in the substrate by it choice, as much as two thirds of the visible color space is covered. Under conditions, when only the substrate emission is present, Commission Internationale d'Eclairage (CIE) chromaticity coordinates for orange color LEDs of (0.54, 0.45, 0.01) for the red, green and blue color, respectively, were determined. 490-nm quantum-well-emitting LEDs were found to be best suited in reaching the technologically important balanced white emission ('White Point') and a value of (0.31, 0.39, 0.30) for the color coordinates close to it was experimentally achieved.

Original languageEnglish (US)
Pages (from-to)1075-1079
Number of pages5
JournalJournal of Crystal Growth
Volume214
DOIs
StatePublished - Jan 1 2000

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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